From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 21 Mar 2016 17:05:13 +0000 (-0700)
Subject: Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
X-Git-Tag: v4.6-rc1~67
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=5518f66b5a64b76fd602a7baf60590cd838a2ca0;p=linux-2.6-block.git

Merge branch 'for-4.6-ns' of git://git./linux/kernel/git/tj/cgroup

Pull cgroup namespace support from Tejun Heo:
 "These are changes to implement namespace support for cgroup which has
  been pending for quite some time now.  It is very straight-forward and
  only affects what part of cgroup hierarchies are visible.

  After unsharing, mounting a cgroup fs will be scoped to the cgroups
  the task belonged to at the time of unsharing and the cgroup paths
  exposed to userland would be adjusted accordingly"

* 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: fix and restructure error handling in copy_cgroup_ns()
  cgroup: fix alloc_cgroup_ns() error handling in copy_cgroup_ns()
  Add FS_USERNS_FLAG to cgroup fs
  cgroup: Add documentation for cgroup namespaces
  cgroup: mount cgroupns-root when inside non-init cgroupns
  kernfs: define kernfs_node_dentry
  cgroup: cgroup namespace setns support
  cgroup: introduce cgroup namespaces
  sched: new clone flag CLONE_NEWCGROUP for cgroup namespace
  kernfs: Add API to generate relative kernfs path
---

5518f66b5a64b76fd602a7baf60590cd838a2ca0
diff --cc kernel/cgroup.c
index 3fe02c152799,2c88149da848..671dc05c0b0f
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@@ -211,12 -211,21 +214,21 @@@ static u64 css_serial_nr_next = 1
   * fork/exit handlers to call. This avoids us having to do extra work in the
   * fork/exit path to check which subsystems have fork/exit callbacks.
   */
 -static unsigned long have_fork_callback __read_mostly;
 -static unsigned long have_exit_callback __read_mostly;
 -static unsigned long have_free_callback __read_mostly;
 +static u16 have_fork_callback __read_mostly;
 +static u16 have_exit_callback __read_mostly;
 +static u16 have_free_callback __read_mostly;
  
+ /* cgroup namespace for init task */
+ struct cgroup_namespace init_cgroup_ns = {
+ 	.count		= { .counter = 2, },
+ 	.user_ns	= &init_user_ns,
+ 	.ns.ops		= &cgroupns_operations,
+ 	.ns.inum	= PROC_CGROUP_INIT_INO,
+ 	.root_cset	= &init_css_set,
+ };
+ 
  /* Ditto for the can_fork callback. */
 -static unsigned long have_canfork_callback __read_mostly;
 +static u16 have_canfork_callback __read_mostly;
  
  static struct file_system_type cgroup2_fs_type;
  static struct cftype cgroup_dfl_base_files[];
@@@ -2020,9 -2021,10 +2041,10 @@@ static struct dentry *cgroup_mount(stru
  	if (is_v2) {
  		if (data) {
  			pr_err("cgroup2: unknown option \"%s\"\n", (char *)data);
+ 			put_cgroup_ns(ns);
  			return ERR_PTR(-EINVAL);
  		}
 -		cgrp_dfl_root_visible = true;
 +		cgrp_dfl_visible = true;
  		root = &cgrp_dfl_root;
  		cgroup_get(&root->cgrp);
  		goto out_mount;
@@@ -5450,14 -5386,13 +5539,16 @@@ int __init cgroup_init(void
  	BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
  	BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
  
+ 	get_user_ns(init_cgroup_ns.user_ns);
+ 
  	mutex_lock(&cgroup_mutex);
  
 -	/* Add init_css_set to the hash table */
 -	key = css_set_hash(init_css_set.subsys);
 -	hash_add(css_set_table, &init_css_set.hlist, key);
 +	/*
 +	 * Add init_css_set to the hash table so that dfl_root can link to
 +	 * it during init.
 +	 */
 +	hash_add(css_set_table, &init_css_set.hlist,
 +		 css_set_hash(init_css_set.subsys));
  
  	BUG_ON(cgroup_setup_root(&cgrp_dfl_root, 0));